Upper incisor position in the sagittal plane when smiling. A photographic and CBCT study.

Background: The aim of this study was to analyze the anteroposterior position between the upper incisors (UI) and the soft tissues based on photographs in which the head has been oriented along the Frankfort Horizontal Plane. Material and Methods: Restrospective case-control study carried out by analizing photographic and CBCT images of 109 patientes. The sample was divided into 4 different groups: 21 normocclusive (N), 29 Class II/1st, 29 Class II/2nd y 30 Class III. All patients were positioned using the Frankfurt plane (FH). From this aligned position of the head, a vertical line was drawn perpendicular to the FH passing through the Soft-Tissue Nasion (LN), and the distance in centimeters from of the UI to this vertical line was measured on both the CBCT and the photo of the patient's profile. Results: The UI was located in front of the LN in the groups N, Class II/1st y Class III (0,4, 0,2, 0,1cm respectively) and behind the LN in the group Class II/2nd (0,2cm). There were significant differences between the Class II/2nd and Normocclusive groups and Class II/2nd and Class II/1st (p<0.001 y p=0.004 respectively). Conclusions: Orthodontic and/or surgical correction of various malocclusions can be planned based on the position of the UI with respect to the LN established in Normocclusive patients. Key words:Upper incisors, facial profile, CBCT, photograph, Frankfurt plane, Soft-Tissue Nasion.

Class II subdivision: Cone beam computed tomography- CBCT Analysis.

BACKGROUND: To estimate whether there is skeletal and/or dental asymmetry in class II subdivision patients, between the Class II side and the Class I side using of cone beam computed tomography (CBCT). MATERIAL AND METHODS: A sample of 30 patients, from a private clinic, retrospectively selected; with a class II subdivision diagnosis requiring treatment, who underwent wide-field CBCT that met the inclusion criteria. The data was processed with Dolphin 3D version 11.95 Premium software. The craniometric points, as well as the spatial orientation scheme of the three-dimensional model were proposed by Craig Minich, et al. (1). RESULTS: The Class II subdivision side and the Class I side of each patient were compared through intramaxillary, intramandibular, and intermaxillary measurements, evaluating each one in three dimensions (sagittal, frontal, and axial). Also, the measurements made from the three-dimensional volume, were contrasted with those generated in the biplane views. The level of significance used was 0.05. Statistical analysis was performed using the R program (R Development Core Team), version 3.4.4. The intraoperative variability was previously verified using the Dahlberg formula. This error is 0.35 -1.10, so the spatial orientation and placement of craniometric points are repeatable and reliable. CONCLUSIONS: Statistically significant differences have been found with respect to skeletal values and dentoalveolar position. Regarding the skeletal findings, the class II subdivision side is narrower and there is a shortening of the condylar branch. In the dentoalveolar position on this side, the upper molar and canine are in an advanced position, the lower molar is posterior and lower than the contralateral and the lower canine is in a delayed position. Furthermore, measurements made from a two-dimensional image cannot be extrapolated with those made directly from a three-dimensional volume. The problem is generated by a deviation in dental position as well as an underlying asymmetry. Key words:Class II subdivision, cone beam computed tomography, skeletal asymmetry, dentoalveolar position.

Comparison of condylar position in normal occlusion, Class II Division 1, Class II Division 2 and Class III malocclusions using CBCT imaging.

BACKGROUND: The aim of this study was to establish the condylar position in a group of patients with normal occlusion, compared to Class II Div 1, Class II Div 2 and Class III malocclusions using CBCT imaging. MATERIAL AND METHODS: Retrospective case-control study carried out by analyzing CBCT images of 80 patients. The sample was divided into 4 different groups with 20 patients each (40 TMJ). All patients were positioned using the Frankfurt plane, parallel to the floor and in maximum intercuspation. The control group included asymptomatic patients with normal occlusion (Less than 2mm of tooth size-arch length discrepancy, positive or negative, 0-2mm overjet, 2-4mm overbite, less than 15o rotations, without facial asymmetries, no previous orthodontic or occlusal treatment, without muscular or articular signs or symptoms in both TMJs) and the experimental group with (class II/1, II/2 and III) malocclusions. RESULTS: The group with normal occlusion had the condyles centrally positioned within the glenoid fossa. The values obtained in this group were considered as optimal and when compared with the other groups with malocclusions. The results established that the position of the condyle was more posterior in class II/2 and more superior in class III patients than the asymptomatic normal occlusion group. CONCLUSIONS: The data obtained in the asymptomatic group with normal occlusion could be used as a reference for future studies. The comparison of these values with those obtained from analyzing the different sagittal malocclusions show significant differences that could be valuable when establishing the diagnosis and the objectives of the treatment plan in orthodontics. Key words:Condylar position, CBCT, dental malocclusion and condylar concentricity.

Roughness and wettability effect on histological and mechanical response of self-drilling orthodontic mini-implants.

OBJECTIVES: Self-drilling orthodontic mini-implants can be used as temporary devices for orthodontic treatments. Our main goal was to evaluate surface characteristics, roughness and wettability, of surface modified mini-implants to increase their stability during orthodontic treatment without inducing bone fracture and tissue destruction during unscrewing. MATERIALS AND METHODS: Modified mini-implants by acid etching, grit-blasting and its combination were implanted in 20 New Zealand rabbits during 10 weeks. After that, the bone-to-implant (BIC) parameter was determined and the torque during unscrewing was measured. The surface characteristics, roughness and wettability, were also measured, onto modified Ti c.p. discs. RESULTS: Acid-etched mini-implants (R a ≈ 1.7 µm, contact angle (CA) ≈ 66°) significantly improved the bone-to-implant parameter, 26 %, compared to as-machined mini-implants (R a ≈ 0.3 µm, CA ≈ 68°, BIC = 19 %) due to its roughness. Moreover, this surface treatment did not modify torque during unscrewing due to their statistically similar wettability (p > 0.05). Surface treatments with higher roughness and hydrophobicity (R a ≈ 4.5 µm, CA ≈ 74°) lead to a greater BIC and to a higher removal torque during unscrewing, causing bone fracture, compared to as-machined mini-implants. CONCLUSIONS: Based on these in vivo findings, we conclude that acid-etching surface treatment can support temporary anchoring of titanium mini-implants. CLINICAL RELEVANCE: This treatment represents a step forward in the direction of reducing the time prior to mini-implant loading by increasing their stability during orthodontic treatment, without inducing bone fracture and tissue destruction during unscrewing.

Effect of temperature on the orthodontic clinical applications of niti closed-coil springs

NiTi spring coils were used to obtain large deformation under a constant force. The device consists on a NiTi coil spring, superelastic at body temperature, in order to have a stress plateau during the austenitic retransformation during the unloading. The temperature variations induced changes in the spring force. Objectives: The aim of this study is to investigate the effect of the temperature variations in the spring forces and corrosion behaviour simulating the ingestion hot/cold drinks and food. Study Design: The springs were subjected to a tensile force using universal testing machine MTS-Adamel (100 N load cell). All tests were performed in artificial saliva maintained at different temperatures. The corrosion tests were performed according to the ISO-standard 10993-15:2000. Results: The increase in temperature of 18oC induced an increase in the spring force of 30%. However, when the temperature returns to 37oC the distraction force recovers near the initial level. After cooling down the spring to 15oC, the force decreased by 46%. This investigation show as the temperature increase, the corrosion potential shifts towards negative values and the corrosion density is rising. Conclusions: The changes of the temperatures do not modify the superelastic behaviour of the NiTi closed-coil springs. The corrosion potential of NiTi in artificial saliva is decreasing by the rise of the temperatures (AU)

Effect of temperature on the orthodontic clinical applications of NiTi closed-coil springs.

UNLABELLED: NiTi spring coils were used to obtain large deformation under a constant force. The device consists on a NiTi coil spring, superelastic at body temperature, in order to have a stress plateau during the austenitic retransformation during the unloading. The temperature variations induced changes in the spring force. OBJECTIVES: The aim of this study is to investigate the effect of the temperature variations in the spring forces and corrosion behaviour simulating the ingestion hot/cold drinks and food. STUDY DESIGN: The springs were subjected to a tensile force using universal testing machine MTS-Adamel (100 N load cell). All tests were performed in artificial saliva maintained at different temperatures. The corrosion tests were performed according to the ISO-standard 10993-15:2000. RESULTS: The increase in temperature of 18 °C induced an increase in the spring force of 30%. However, when the temperature returns to 37 °C the distraction force recovers near the initial level. After cooling down the spring to 15 °C, the force decreased by 46%. This investigation show as the temperature increase, the corrosion potential shifts towards negative values and the corrosion density is rising. CONCLUSIONS: The changes of the temperatures do not modify the superelastic behaviour of the NiTi closed-coil springs. The corrosion potential of NiTi in artificial saliva is decreasing by the rise of the temperatures.

Lower incisor position in different malocclusions and facial patterns

Introduction: The position of lower incisor has been of considerable concern when planning an orthodontic treatment, having been recognized as one of diagnostic keys, Very important in the development of malocclusion and facial pattern. Objectives: In this study we claim to determine the importance of the position and inclination of lower incisor in the different malocclusions and facial patterns, and to base which of the cephalometric measurement parametersare the mostreliable. Material and Methods: Ninety lateral radiographies were taken, and they were classified by skeletal malocclusion and facial pattern. These teleradiographies have been performed cephalometric analysis, which include lower incisorposition belong the following analysis: Ricketts, Riolo, Tweed, McHorris, Jarabak-MSE and Holdaway. Study Design: Cross-sectional study where we perform statistical analysis Anova test, Pearson correlations and Bonferroni analysis. Results: The analyzed measurements present a statistically significant differentiation in lower incisor inclination respect to the anterior cranial base, McHorris angle, angulation of lower incisor respect to occlusal plane and mandibular plane. Conclusions: There are statistically significant differentiation in lower incisor position and inclination respect the malocclusion and individual facial pattern (AU)

The segmented arch approach: a method for orthodontic treatment of a severe Class III open-bite malocclusion.

An open bite is a common malocclusion, and it is generally associated with several linked etiologic factors. When establishing the treatment plan, it is essential to consider every aspect of the various etiologic causes and their evolution; this will help to correct it. This article reports the case of a girl aged 10.7 years with a skeletal Class III malocclusion and an open bite. The treatment mechanics were based on compensatory dental changes performed to close the bite and correct the skeletal Class III malocclusion. The patient had a deep maxillary deficiency, and the lower facial third was severely enlarged. In this article, we aimed to describe a simple mechanical approach that will close the bite through changes in the occlusal plane (segmentation of arches). It is an extremely simple method that is easily tolerated by the patient. It not only closes the bite effectively but also helps to correct the unilateral or bilateral lack of occlusal interdigitation between the dental arches. A Class III patient with an anterior open bite is shown in this article to illustrate the effectiveness of these treatment mechanics.

True vertical validation in facial orthognathic surgery planning.

OBJECTIVES: To validate the effectiveness of the original standards of True Vertical (TV) Subnasal Line in orthognatic surgery planning. The present study evaluates the changes occurring in patients with skeletal Class II alterations programmed for orthognathic surgery with a view to improving their facial profile. STUDY DESIGN: [corrected] We showed a series of black profiles (composed by a first control group of subjects with normal occlusion, and another two additional groups comprised patients before -Group 2- and after orthognatic surgical correction of Class II malocclusion -Group 3-) for three groups of observers (orthodontists, surgeons and laypeople). The facial images became black silhouettes in order to determine a series of parameters (including aesthetic assessment) by means of the observers. Their observation were assessed using a 5-point Likert scale. RESULTS: The sample was composed of 52 profile's subjects who were tested for a total of 72 observers. Aesthetic assessment yielded mean scores of 2.57, 1.67 and 2.46 for groups 1, 2 and 3, respectively. There was a statistically significant difference (p<0.001) between group 1 versus group 2. There were no significant differences in terms of observer assessment of aesthetics, with the exception of a wider perception range among the orthodontists. Regarding the studied profile measures, significant differences were recorded for point B' and Pg' (p<0.02) between groups 2 and 3 (i.e., pre- versus post-surgery). CONCLUSIONS: The results of our study suggest the subnasale vertical and sagittal measures of the lower third of the face are decisive in facial aesthetics, and therefore also for the planning of orthognathic surgery. Consequently, these aesthetic parameters can be used as an objective tool for the planning of orthodontic treatment. Key words:Facial profile, Class II, orthognathic surgery, cephalometric analysis, facial soft tissue, subnasale vertical.

Lower incisor position in different malocclusions and facial patterns.

INTRODUCTION: The position of lower incisor has been of considerable concern when planning an orthodontic treatment, having been recognized as one of diagnostic keys, Very important in the development of malocclusion and facial pattern. OBJECTIVES: In this study we claim to determine the importance of the position and inclination of lower incisor in the different malocclusions and facial patterns, and to base which of the cephalometric measurement parameters are the mostreliable. Material and methods. Ninety lateral radiographies were taken, and they were classified by skeletal malocclusion and facial pattern.These teleradiographies have been performed cephalometric analysis, which includelower incisor position belong the following analysis: Ricketts, Riolo, Tweed, McHorris, Jarabak-MSE and Holdaway. STUDY DESIGN: Cross-sectional study where we perform statistical analysis Anova test, Pearson correlations and Bonferroni analysis. Results. The analyzed measurements present a statistically significant differentiation in lower incisor inclination respect to the anterior cranial base, McHorris angle, angulation of lower incisor respect to occlusal plane and mandibular plane. CONCLUSIONS: There are statistically significant differentiation in lower incisor position and inclination respect the malocclusion and individual facial pattern.

Maloclusión ortodóncica severa de clase II: cirugía versus distracción / Severe class II orthodontic malocclusion: distraction versus surgery

La maloclusión esquelética severa de clase II conlleva la necesidad de tratamientos complejos para la corrección completa de la alteración. La cirugía supone la solución en determinados pacientes, sobre todo fuera de crecimiento. Por otro lado, la distracción osteogénica es la alternativa para casos en crecimiento y sobre todo para el tratamiento de severas anomalías dentofaciales. En este artículo, realizamos una revisión de la literatura, para intentar exponer las opiniones contrapuestas de los diversos autores que apoyan las diferentes alternativas. Intentamos exponer las controversias y fijar las pautas que se han de seguir en la resolución de los trastornos severos de clase II que serán abordados mediante estos 2 procedimientos (AU)

Obstructive Sleep Apnea Syndrome (OSAS). Review of the literature

Obstructive sleep apnea and hypopnea syndrome is characterized by repeated airway collapse during sleep. The literature describes multiple causes of the disease. The main cause is a reduction of the expansion forces of the pharyngeal dilator muscles, as in situations of genioglossal muscle dysfunction, and discoordination between the inspiratory activity of the muscle and respiratory effort, which play an important role in progression of the disease. Other described causes are soft tissue disorders, such as macroglossia or tonsillar hypertrophy, and skeletal structural alterations such as micrognathia and retrognathia. The syndrome is also more frequent in obese people, where the accumulation of fat in the neck region produces narrowing of the pharyngeal airway, thereby diminishing the passage of air. This review focuses on the pathogenesis, epidemiology, main features and diagnosis of the disease, and on its main forms of treatment (AU)

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Arcos segmentados. Mecánica de cierre en las mordidas abiertas. Aportaciones clínicas / Segmented arches. Closure mechanism in open bite. Clinical contributions

La mordida abierta es una entidad muy frecuente asociada a una etiología multifactorial. De ahí que en el tratamiento haya que considerar todo el recorrido en su aparición, intentando llegar hasta los procesos etiológicos que permitan la corrección de la misma. En este trabajo, presentamos una mecánica sencilla que nos permite, mediante modificaciones en el plano oclusal (segmentación de los arcos), conseguir el cierre de la misma; este método resulta de extrema sencillez y fácilmente tolerable por el paciente. No sólo aporta un sistema eficaz en el cierre, sino una ayuda en la mecánica habitual para corregir situaciones de falta de oclusión parcial, uni o bilateral de las arcadas dentarias (AU)

Open bite is a highly common entity that is associated with a multifactorial etiology. Hence, all the steps involved in its development should be considered in its treatment, attempting to identify the etiological processes that allow this entity to be corrected. in this article, we present a simple mechanism that allows closure to be achieved through changes in the occlusal plane (arch segmentation). This method is extremely simple, and is easily tolerated by the patient. Moreover, this mechanism not only provides an effective system for closure, but also helps to correct situations of uni- or bilateral malocclusion of the dental arches (AU)

The relationship between malocclusion, benign joint hypermobility syndrome, condylar position and TMD symptoms.

The current study investigated the association between temporomandibular disorders, malocclusion patterns, benign joint hypermobility syndrome and the initial condylar position. One hundred sixty-two subjects were analyzed using the Rocabado Temporomandibular Pain Analysis; Helkimo Index parameters; the Carter-Wilkinson modified test; and a mounting cast with condylar position indicator registration (MPI). The study revealed a significant association between: 1. Delta H, skeletal pattern (p = 0.034); 2. Delta Y, transversal malocclusion (p = 0.04); 3. right and left, Delta Z, right and left posteroinferior synovial pain (p < 0.05); 4. hypermobility scale, gender (p < 0.001), malocclusion pattern (p = 0.021); 5. TMJ function impairment, gender (p = 0.043); 6. sagittal malocclusion pattern, right temporomandibular pain analysis joint (TPAJ) (p = 0.0034); 7. TMJ function impairment, left and right TPAJ (p = 0.007); and 8. mandibular motion, left and right TPAJ (p = 0.035, p = 0.015). The conclusion was that anterior crossbite and condylar displacements in the vertical plane are risk factors in developing TMJ symptoms.

Obstructive sleep apnea syndrome (OSAS). Review of the literature.

Obstructive sleep apnea and hypopnea syndrome is characterized by repeated airway collapse during sleep. The literature describes multiple causes of the disease. The main cause is a reduction of the expansion forces of the pharyngeal dilator muscles, as in situations of genioglossal muscle dysfunction, and discoordination between the inspiratory activity of the muscle and respiratory effort, which play an important role in progression of the disease. Other described causes are soft tissue disorders, such as macroglossia or tonsillar hypertrophy, and skeletal structural alterations such as micrognathia and retrognathia. The syndrome is also more frequent in obese people, where the accumulation of fat in the neck region produces narrowing of the pharyngeal airway, thereby diminishing the passage of air. This review focuses on the pathogenesis, epidemiology, main features and diagnosis of the disease, and on its main forms of treatment.

External apical root resorption in maxillary root-filled incisors after orthodontic treatment: A split-mouth design study

Introduction: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. Methodology: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the root resortion and the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the endodontically treated incisor and that in its contralateral incisor with a vital pulp. The student’s t-test, chi-square test and logistic regression analysis were used to determine statistical significance. Results: There was no statistically significant difference (p > 0.05) between EARR in vital teeth (1.1 ± 1.0 mm) and endodontically treated incisors (1.1 ± 0.8 mm). Twenty-six patients (68.4%) showed greater resorption of the endodontically treated incisor than its homolog vital tooth (p > 0.05). The mean and standard deviation of PPR were 1.0 ± 0.2. Multivariate logistic regression suggested that PRR does not correlate with any of the variables analyzed. Conclusions: There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root-filled incisors and their contralateral teeth with vital pulps (AU)

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External apical root resorption in maxillary root-filled incisors after orthodontic treatment: a split-mouth design study.

INTRODUCTION: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. METHODOLOGY: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the root resortion and the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the endodontically treated incisor and that in its contralateral incisor with a vital pulp. The student's t-test, chi-square test and logistic regression analysis were used to determine statistical significance. RESULTS: There was no statistically significant difference (p > 0.05) between EARR in vital teeth (1.1 ± 1.0 mm) and endodontically treated incisors (1.1 ± 0.8 mm). Twenty-six patients (68.4%) showed greater resorption of the endodontically treated incisor than its homolog vital tooth (p > 0.05). The mean and standard deviation of PPR were 1.0 ± 0.2. Multivariate logistic regression suggested that PRR does not correlate with any of the variables analyzed. CONCLUSIONS: There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root-filled incisors and their contralateral teeth with vital pulps.

Improvement in adhesion of the brackets to the tooth by sandblasting treatment.

In oral orthodontic treatments, achievement of a good adhesion between brackets and teeth surfaces is essential. One way to increase adhesion is to apply a surface treatment of teeth facing surfaces through the projection of abrasive particles to produce a surface roughness which improves adhesion of the bracket to the tooth, because of the significantly increased contact between the two surfaces. The effect on adhesion through the use of this technique in different types of brackets, as well as through the use of different blasting particles, however, is yet not well described. In this study we have included three types of brackets which are commonly used in orthodontic therapies (two of them a mesh-type and the third one a micro-milled type) with a contact surface area of 11.16, 8.85 and 6.89 mm(2) respectively. These brackets were used combined with a sandblasting treatment with two different types of abrasive particles, alumina (Al(2)O(3)) and silicon carbide (SiC) and applied to natural teeth in vitro. The abrasive particles used are bio-compatible and usually used in achieving increased roughness for improved adherence in biomedical materials. Sandblasting was performed at 2 bars for 2 s; three particle sizes were used: 80, 200 and 600 µm. Non-blasted samples were used as control. Each of the pieces were cemented to natural teeth with a self-curing composite. Samples were stored in physiologic serum at 5°C temperature. Tensile tests were performed with a universal testing machine. Brackets treated with sandblasted particles were measured to have an increased adhesion as compared to the control sample. The highest bond strength was measured for samples sandblasted with alumina particles of 80 and 200 µm combined with micro-milled brackets. The recorded stresses did not exceed the tensile strength of tooth enamel.